Encryption in XML file

[Mike]

I am encrypting string values and storing them in an XML file using the
Crypto class in the MSDN Signature sample and the DataSet class to
read/write XML.

Which encoding method should I use (Unicode, UTF8?) to convert strings to
byte arrays? The Crypto class uses byte arrays for encrypting and
decrypting.

 

[Jon Skeet [C# MVP]]

I am encrypting string values and storing them in an XML file using the
Crypto class in the MSDN Signature sample and the DataSet class to
read/write XML.

Which encoding method should I use (Unicode, UTF8?) to convert strings to
byte arrays? The Crypto class uses byte arrays for encrypting and
decrypting.

Use Convert.ToBase64String and Convert.FromBase64String.

 

[Mike]

convert.FromBase64String("9/8/2004 10:18AM")

Run-time exception thrown : System.FormatException - FormatException

The documentation for FromBase64String seems to say that it doesn't support
the : character. How should I convert a time string to a byte array?

 

[Jon Skeet [C# MVP]]

convert.FromBase64String("9/8/2004 10:18AM")

Run-time exception thrown : System.FormatException - FormatException

The documentation for FromBase64String seems to say that it doesn't support
the : character. How should I convert a time string to a byte array?

My mistake - I thought you were asking about how to store the binary
data once it had been encrypted.

I'd suggest using UTF-8 to convert from a string to a byte array to
start with. So, you'll end up with:

Original data -> UTF-8 encoded string -> encrypted bytes->Base64 string

That's what you put in your XML file. Then you go the other way:

Base64 string->encrypted bytes -> UTF-8 encoded string -> original data

 

[Mike]

Thanks. I am using Unicode instead of UTF-8 and it seems to be working. Do
you think there will be a problem if I leave it as Unicode?

 

[Jon Skeet [C# MVP]]

Thanks. I am using Unicode instead of UTF-8 and it seems to be
working. Do you think there will be a problem if I leave it as
Unicode?

Well, it'll usually be twice as big as it would be with UTF-8 (the
"usually" meaning "if all the text data is just ASCII", but it'll still
work.

 

[Mike]

Cool! Thanks Jon - that helped a lot!!!

Well, it'll usually be twice as big as it would be with UTF-8 (the
"usually" meaning "if all the text data is just ASCII", but it'll still
work.